Slope of a Line



Warm Up

State whether or not the equation is linear or not linear.
1) y = 3x - 2

2) 2x + 3y = 6

3) x = -1

4) y = 2

5) 2xy = 7



What is the slope of a line?

Slope is a fraction that tells you how steep the line is going up or down. We always look at a line from left to right.


Learning Objectives

  1. Identify when a line has a positive slope, negative slope, zero slope or undefined slope.
  2. Find the slope of a line given two points on a line.



Lesson Notes


Slope is sometimes called m. When you see the letter m this means slope. Remember this because you will need to know what m is when you get to lessons 3,4,and 5.

Slope is sometimes referred to as rise over run and written as a fraction. The numerator is the rise and the denominator is the run.

The rise is the vertical or up and down change in the graph. The rise tells you if the line is a positive or negative slope.

The run is the horizontal or left and right change in the graph. For the most part we will think of run as going to the right. There will be a few times that I will have you go left, but only when you run out of room on a graph. We will discuss this further on in the lesson.

  • Lines with positive slope rise from the left to the right.
  • Lines with negative slope fall from the left to the right.
  • Lines with undefined slope are vertical (up and down).
  • Lines with zero slope are horizontal (flat).

Here are some visuals to help you with this definition:
negslope.gif
Negative Slope

negslope2.gif The rise is -2 and the run is 1.
Remember that when a line has a negative slope it falls left to right.





posslope.gif
Positive Slope


The rise is 2 and the run is 3. This means that for every 2 units up the line travels 3 units to the right.

Remember that when a line has a positive slope it rises up left to right.



zeroslope.gif
Zero Slope

slope = 0
There is no rise only run. This means that the numerator or top of the fraction is zero.
Remember that when a line is horizontal, with no up or down, the slope is 0.





undslope.gif
Undefined Slope

slope = undefined
There is no run only rise. This means that the denominator of the fraction is zero.
Remember that when the line is vertical the slope is undefined.




This next picture is called the house that slope built. Notice the roof walls and floor represent a type of slope.


house.gif
The House That Slope Built



Things to remember when finding slope if you have two points.

  1. m represents the slope of a line
  2. [y2-y1] represents the rise
  3. [x2-x1] represents the run
  4. divide the rise and run



View Video

The following video describes how to find the slope of a line using two points. If you are having trouble viewing this video right click on the black screen and select zoom to full screen.







PowerPoint

View the following PowerPoint for examples on finding the slope of a line given two points.
View as a PowerPoint
View as a PDF



Assignment

Now it's your turn. Here is your assignment. With each of the following problems find the slope with the two points. Click on the link below to view the assignment. This assignment can be edited and saved on your computer. To turn this assignment in each student is to do one of the following things.

  1. Save the edited version on your computer and email the file as an attachment to Mr. Clarke. Use the following link to email. troy.clarke@canyonsdistric.org
  2. Print out a copy of the worksheet and hand in the completed assignment in class.
Slope Assignment


Quiz

Slope

Axis Intercepts



Slope Intercept Form



Point Slope Form



Standard Form



For Teachers

Slope Lesson Plan